Organomodified siloxanes are used in a very wide variety of applications. The properties of organomodified siloxanes can be specifically adjusted by the type of modification employed and also by the modification density.
Thus, for example, with allyl polyethers, organophilic or nonionic hydrophilic groups can be bonded to a siloxane backbone. Compounds of this type are used, for example, as polyurethane foam stabilizers and as antifoams in fuels.
By contrast, through reaction with alpha-olefins, the siloxane is linked to oleophilic groups. The silicone waxes obtained in this way serve, for example, as additives in cosmetic applications.
In many fields of application, it is found that the effect of the siloxane depends decisively on the compatibility with the corresponding formulation. Suitable emulsifiers are, for example, siloxanes which, besides aliphatic groups based on alpha-olefins, carry polyethers, such as, for example, the commercial product ABIL® EM 90 from Evonik Goldschmidt GmbH, Germany.
Since polyether-containing compounds have recently received increasing criticism, there is a need for siloxane-based emulsifiers which carry no polyether groups, but at the same time have good emulsifying and dispersing properties.
For example, glycerin derivatives or polyglycerin derivatives can replace the polyether groups as a hydrophilic component. Polyglycerin-modified siloxanes are described, for example, in EP 1213316. In the application EP 1550687 (Shin-Etsu), glycerin-modified siloxanes are used in emulsions. Polyglycerin-modified siloxanes are also commercially available, for example from Shin-Etsu under the names KF-6100 or KSG-710.
However, the glycerin-modified siloxane compounds described hitherto are generally not suitable for adequately stabilizing emulsions and dispersions—as is necessary, for example, for commercial, and cosmetic formulations. Formulations have to be storage-stable in order to ensure appropriate durability and constant quality of the end product. For this, the emulsions or dispersions have to exhibit a constantly stable composition and homogeneity without oil separation or water separation or solids separation over a period of several months and at various temperatures. Specifically in the case of cosmetic emulsion preparations for make-up and sunscreen applications, which additionally comprise inorganic pigments such as, for example, titanium dioxide or iron oxides, it is often difficult to prepare cosmetic preparations which are characterized by good long-term stability and by a very good pigment dispersion. Here, the glycerin-based silicone emulsifiers described in the prior art generally have inadequate emulsion stabilization. Emulsions which are prepared with the help of the glycerin-containing silicone emulsifiers described in the prior art can separate upon storage and thus lead to inadequate stability and nonreproducible results.